In recent years great emphasis has been placed on improving the fuel economy of passenger vehicles, However, on a proportional basis large tractor-trailer rigs use far more fuel than passenger vehicles. While in many cases the same technological advances that have improved passenger vehicle fuel economy can be and have been used on tractor-trailer rigs there are major aerodynamic differences between those types of vehicles which limit the benefit of those advances.
Tractor-trailers are generally box-shaped. While that shape can be highly advantageous when hauling goods, the shape is aerodynamically inefficient. The poor aerodynamic efficiency of tractor-trailers combined with their height and weight results not only in poor fuel economy but also increases stresses upon engines, transmissions, and drive trains. The box-shape results in even more detrimental aerodynamic drag when the tractor is pulling multiple trailers such in tandem or triple-trailer configurations. Turbulent air streams are generated by the box-shape at highway speeds. Those air streams often get caught between trailers, resulting in even worse fuel economy and higher operating costs. Owner profits are reduced while the cost of transporting goods is increased.
Accordingly, there exists a need for devices which can improve the aerodynamic efficiency of tractors that pull multiple trailers. Beneficially such devices would reduce the effects of turbulent air streams between trailers while improving fuel economy. In practice such devices should not negatively impact turning or other maneuvering operations and should not increase visibility problems, either of the tractor operator or of others on the highway. Ideally such devices would be easy to use, suitable for being made available at relative low cost, easy to install and to remove, effective and would not endanger either the tractor operator or others on the highway.